The function of electrical switching devices, such as low-voltage circuit breakers, is to decouple one or more electricity-consuming loads from a voltage supply network when a specific malfunction occurs. The archetypal malfunction is the occurrence of a short-circuit current, and the circuit breakers are conventionally designed to move a switching element in the event of such a short-circuit current and thereby decouple the connection between loads and voltage supply network.
For decades electrical loads in the industrial domain have been protected against overcurrents and short-circuits by means of low-voltage or compact molded-case circuit breakers (MCCBs) which interrupt the electrical circuit in the fault situations described.
Electrical switching devices or low-voltage circuit breakers are available in very different design formats. These differ essentially in terms of their current-carrying capacities and consequently considerably in terms of their size.
Electrical switching devices such as low-voltage circuit breakers have one or more connecting arrangements comprising a terminal having in each case a connection opening in order to attach electrical connections, such as cables, busbars or cable shoes, to the electrical switching device. However, there are also terminals to which two or six cables, for example, can be connected. For example, a user in the field of low-voltage circuit breakers can install different terminal variants which allow, for example, bare cables, perforated or unperforated copper busbars or even cable shoes to be connected directly.
For assembly, it is necessary to install a connecting arrangement, also referred to as connection accessories, in the switch housing. Typically, the terminal is first secured to an electrical contact of the electrical switching device before a terminal screw which is subsequently intended to retain the cable in the terminal is inserted into the terminal. This means either that there must be a sufficiently large connection opening or cable opening present in the terminal, that it must be possible to open the electrical switching device from the front side of the switching device, or that there must be sufficient space above between the terminal and the switching device housing to enable the terminal screw to be installed. If this is not possible, the terminal, including the terminal screw, cannot be installed in the low-voltage circuit breaker.
Another possibility for securing a terminal to an electrical switching device is to mount the terminal from the rear side of the switching device. In this case the terminal screw could already be in a screwed-in position in the terminal. With this approach, however, it would be necessary to disassemble the electrical switching device, in particular a low-voltage circuit breaker, every time the terminal attachment is checked.
It is problematic to install a connecting arrangement comprising a terminal, a fixing screw for securing the terminal to an electrical contact of the electrical switching device and a terminal screw for retaining an electrical connection, in particular a cable, in the connection opening, also referred to as the terminal opening, when there is only a small amount of installation space available. If the installation space is too small for a connecting arrangement of said type, recourse can be made to a different connecting arrangement or terminal variant which can be installed in a different way. Thus, rather than being screwed onto the electrical contact, the terminal can be clamped behind the electrical contact. However, a terminal which is positioned/clamped behind the electrical contact allows very small electrical connections, in particular cables, to deviate sharply to the left or right because of its large connection opening or cable opening. Furthermore, these terminals are bigger and heavier than a terminal which has a small cable opening and is designed especially for very small cables. The small cable opening now no longer allows the terminal screw to be installed through it and above between terminal and housing wall there is insufficient space for the installation, because the terminal must first be secured to the electrical contact.